Steam-engine



'DQW. SHAWKB P. w. BR-OWN. I STEAM ENGINE. NO; 244,825. Patented July26, 1.881.

A WITNESSES! I /3 lgnyim $BY u' KTERS. Plwlo-Liliw mphon Wnlhinglcn. 0.0

UNITED STATES DANIEL W.'SHAW AND PLEASANT W. BROWN,

TENNESSEE.

PATENT OFFICE.

OF 'MURFREESBOROUGH,

STEAM-ENGINE.

SPECIFICATION forming'part of Letters Patent No. 244,826, dated July 26,1881.

' Application filed February 5, 1880.

To all whom it may concern:

Be it known that we, DANIEL W. SHAW and PLEASANT W. BROWN, ofMurfreesborough, in the county of Rutherford and State of Tennessee,have invented a new and useful Improvement in Steam-Engines, of whichthe followingis a specification.

Figure 1 is a plan of the device, partly in section. Fig. 2 is alongitudinal sectional elevation on line m, Fig. 1. Fig. 3 is asectional end elevation on line 3 3 Fig. 2.

Similar letters of reference indicate corresponding parts.

The object of this invention is to economize steam and to cause aconstant equal pressure or strain upon the driving-shaft of the engine.

The invention is an improvement in the class of steam-engines havingmore than one movable piston working in the same cylinder, each of whichis separately connected with the crank-shaft. The improvement isembodied in features of construction and the combination of partshereinafter described and claimed.

In the drawings, A represents the crankshaft of the engine.

a a represent the cranks,,to which are attached the pitmen B, thatconnect with the rods 0 of the end pistons, D D, which are placed withinthe cylinder E.

1) represents the crank that carries the pitman E, which is attached tothe piston-rod G of the central piston, H.

It will be seen that the piston-rod G passes through the center of theouter piston, D, and is secured to the center of the central piston, H,and that thepiston-rods (3 0 pass through the piston D, and are securedthereto on either side of the rod G, and at equal distances therefrom,and also through the piston H, and have their ends secured in the pistonD, and by this construction and arrangement the central piston, H, issteadied in its movement, and the movementof the pistons D D madesynchronous.

I I are the cross-heads, moving in suitable bearings.

c c are vthe steam-supply ports, andK the steam-chest, of the cylinderE. When the parts are in the position shown in Fig. 1 the steam enteringthe port a between the pistons H and D will force said pistons apart inopposite directions. The pistons D D, moving toward one end of thecylinder while the central piston, H, is moved toward the opposite endthereof, as the central piston, H, and the piston D approach fromopposite directions near to the port 0, the steam, in turn, enteringport 0, forces the said pistons H and D apart again in oppositedirections, and the cranks a, a, to which the pistons D D are connected,being set opposite the crank O, to which the piston H is connected, itwill be seen that by the simultaneous movement of the three pistons thecrank-shaftA is at the same moment pushed and pulled in oppositedirections, so that the strain upon the crank shaft A (the pistons beingall of the same diameter) is equal at every point of its revolution.

It is designed that the cylinder E shall be provided with proper valvesand exhaustports for regulating the supply and exhaust of steam.

Having thus fully described our invention, we claim as new and desire tosecure by Letters Patent- In a steam-engine, the combination, withpitman cranks and rods, of a frame attached to bed-plate, and providedwith a groove at top and bottom, and three slides connected by verticalcross-heads working side by side in said frame, as shown and described,whereby a positive movement transmits the power directly from thepiston-heads to the pitmancranks.

DANIEL WEBSTER SHAW. PLEASANT W. BROWN.

Witnesses:

FRANK HOWARD, H. O. CHAPMAN.

